Jenifer, who lives in Colorado, USA, suffers from an ultra rare disorder that leaves sufferers locked in permanent infancy.

Known until recently only as ‘Syndrome X’, the families of those affected by this dramatic arrest in development were offered very little relief from doctors, who were stumped by the shocking symptoms.

But now a pioneering scientist has been able to decipher the genetic causes behind the disorder, sharing his findings in a new television show.

Dr Richard Walker, an ageing specialist from Florida, worked with the University of South California has devoted a large portion of his professional life to working out why Jenifer, along with other patients like Alyssa Gomez and Gabby Williams, still look and behave like tiny babies despite their advancing years.

When a potential sufferer was identified in three-year-old Layla Sapp, from Oklahoma, Dr Walker was determined to find a genetic link between the four girls.

Dr Richard Walker, an ageing specialist from Florida has devoted a large portion of his professional life to working out why people such as Alyssa still look and behave like tiny babies despite their advancing years

As Jenifer can’t communicate, she often throws temper tantrums and has bitten through her mother’s skin in a rage.

Renee is concerned that now Jen is too old for a place at a special needs school, she will need to be cared for continually by her family.

“There are day care centres for adults with special needs where they teach them how to cook and look after themselves,” she said.

“But obviously, Jen is never going to be able to do that.”

A routine blood test early in Renee’s pregnancy revealed that Jen was developing atypically.

“When I was about four or five months pregnant, I had an AFP test done and I knew Jenifer was going to be born with some time of disability,” she said.

“The doctors actually brought up adoption and abortion and, I mean, it wasn’t even an option. You don’t just throw a child away because she is going to be different.”

As doctors struggled to find an explanation for Jen’s stunted development, Renee reached out to Dr Walker.

Blood samples from each of the ‘Syndrome X’ children were sent to a high tech laboratory in San Francisco for ‘Whole Genome Sequencing’ - a new technology that can identify damaged genes.

Carried out by the world’s number one geneticist, Dr Radoje Drmanac, the experiment found the connection between the girls that Dr Walker was looking for.

Dr Drmanac said: “Genomics is an exciting new field of science. We have technology to find this one mutation in a billion letters. It’s like looking for a spelling error in a thousand books.”

The syndrome has now been named Neotinic Complex Syndrome and Dr Walker believes that not only will the discovery help the girls suffering from the syndrome, but also lead to advances in the treatment and understanding of conditions like Alzheimer’s, Parkinsons and Dementia.

Dr Richard Walker, an ageing specialist from Florida has devoted a large portion of his professional life to working out why people such as Alyssa still look and behave like tiny babies despite their advancing years